What is Sources: Definition and 537 Discussions

A tertiary source is an index or textual consolidation of primary and secondary sources. Some tertiary sources can be used as an aid to find other sources. The exact definition of tertiary varies by academic field.
Academic research standards generally do not accept tertiary sources as citations.

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  1. E

    Engineering Design a Circuit Using Diodes, Resistors and Voltage Sources

    Hello, I have this problem: design a circuit using diodes, resistors and voltage sources to obtain the input function. And the input function is Iin vs Vin plot with following points connected as straight lines: (2V,0mA), (3V,2mA), (4V,6mA). I guess I need a hint on what kind of topology...
  2. R

    Sources of Electrons in Photosynthesis & Respiration

    I am not sure about sources of electrons in photosynthesis and respiration. If someone can explain this that would be great?? I think the source of electrons for photosynthesis would be water and light. Am I correct? Still reading about respiration... Also occurrence in photosynthesis...
  3. M

    Sources of musical sound problem

    Question: Organ pipe A, with both ends open, has a fundamental frequency of 450 Hz. The third harmonic of organ pipe B, with one end open, has the same frequency as the second harmonic of pipe A. Use 343 m/s for the speed of sound in air. a)How long is pipe A? b)How long is pipe B? I...
  4. Amith2006

    Definition of coherent sources

    Sir, Coherent sources are defined as sources having same frequency and constant phase difference. In some books it is given that coherent sources have constant phase difference only. Which is correct?
  5. D

    Calculating Voltage and Current for an AC Source | 180sin377t Equation Explained

    The voltage of an AC source is given by the equation v=180sin377t where v is the instantaneous voltage and t is in seconds. (a) what is the rms value of the voltage? (b) what is the frequency of the ac source? (c) if this voltage is connected to a 40 ohm resistor, find the equation that...
  6. T

    Programs Exploring PhD Scholarships & Financial Sources in the US

    hi, I am not an US citizen, but have a plan to study phD in US. However, I have financial problem. My question is: If I am awarded a phD scholarship, is there still any other "financial sources" that I can work for to earn some more money? If I spend just enough for basic living...
  7. D

    Sources of errors on Determinating Faraday's Constant experiment

    Give three sources of error in your calculation in Part B. Which of these contributions the greatest source of error? Explain. In part B i did 6 steps in determination of Faraday's Constant. 1. I marked two copper strips (to distinguish them) and weigh them 2. Attach these to the...
  8. L

    Interconnections Of Ideal Sources

    Hey There, Can anyone help me and maybe can tell when interconnections of ideal dependent or independent ideal sources are valid? I need it please and if anyone got any link, i will be very thankfull, thank you
  9. M

    Determine sources being charged

    i keep getting stuck in this problem, i don't see what I am doing wrong. the problem says to determine which sources absorb positive power, then show that algebraic sum of the five absorbed power values is zero. i have attached a picture of the circuit, and here is what i have done: Starting...
  10. Astronuc

    Online Sources for Statistics and Statistical Analysis

    I was searching for references on statistics and found this - StatSoft Electronic Texbook - http://www.statsoft.com/textbook/stathome.html Elementary Concepts in Statistics - http://www.statsoft.com/textbook/esc.html Basic Statistics - http://www.statsoft.com/textbook/stbasic.html
  11. G

    Alternate sources for 3K background radiation?

    I am new to this forum, and am not certain whether this question merits a serious response, or will be laughed out. I have studied undergrad relativity (Various metrics etc), but have not made much headway with tensor maths - yet. So here goes... Something i have often wondered, is whether...
  12. D

    Sources of Error in Standing Waves Lab

    I have to write an error analysis for my lab report, but am having some trouble making my sources of error clear and precise. The lab itself was a very basic investigation of the relationship between the tension, frequency, and mass per unit length (mu) in a standing wave pattern. Some...
  13. V

    Comparing Current Sources: Op Amp vs. Transistor

    What is the difference between a current source using an op amp and one using a single transistor? Why would you use one over the other, etc? Thanks!
  14. K

    Low-End DJ Mixer for Car Sound Sources

    Hi. I am thinking aout purchasing a three or four channel low-end DJ Mixer for the multiple sound sources I have in my car. A few questions: What's the deal with all the microphone inputs? I just want to plug in an MP3 Player, a CD Player, and another sound source all at once. There won't...
  15. T

    Sources of non-linearity in detector

    Basic setup is a photo-detector coupeled with an amplifier. Questions is what are possible sources of non-linear behaviour ? Now, one possible source is obviously the amplification of background noise, but what other sources are there ? Alternatively could one give me a book or website to...
  16. K

    Tsunamis and Nuclear Power: Potential Risks and Precautions

    I would like you know everybody's general thoughts on alternative fuels, and aleternative energy. Personally, I think ethanol is a great thing and I'm hoping it gets picked up by more manufacturers. Hydro-fuel cells also seem quite promising, being more efficient and not producing hazardous...
  17. J

    Can You See Other Stars While Sitting on the Sun?

    This is a thing that I would like help with. If I was sitting on the sun (impossible I know) would I see light from any other source entering my location? If not why not?
  18. S

    News What do you consider legitimate sources?

    If everyone could tell me exactly what news organizations or whatever, they would consider legitimate sources? For me, I mostly trust any most mainstream news organizations to an extent. Even CNN and FOX can't bend the truth too much, but I will need to double check things if I see them...
  19. R

    Sink and Sources in Fluid Mechanics: Attraction, Repulsion, and Vortices

    Dear Friends, I have some questions about the efects of sink, sources and vortices. Both sink and source in fluids mechanics, are a region near a point that attracts or repels, for example, a particle. In the case of a vortice, in adition, a particle will be atract and approach towards the...
  20. Astronuc

    Sources of information on Physics of Condensed Matter

    SpectroscopyNow.com http://www.spectroscopynow.com/Spy/basehtml/SpyH http://www.spectroscopynow.com/Spy/basehtml/SpyH/1,1181,0-8-1-0-1-about_this_site-0-0,00.html the site.
  21. Q

    Producing umbra and penumbra with light sources

    when two souces are used, how many sources must be blocked by the object to produce the unbra? and the penumbra? I looked it up in my textbook and on the internet and i still can't find the answer.
  22. T

    Cherenkov-effect + other EM relativity derivations: sources pls?

    (Any help whatsoever is greatly appreciated) I am looking for good online sources to help me understand relativistic formula's for the equations of Maxwell, and all the stuff that follows from it (like Cherenkov radiation). I realize that's a pretty vague description, so if there is no...
  23. M

    How many primary sources of energy do we have?

    I think we have 3 primary sources on the Earth. 1st – Sun (nuclear fusion) Coal, oil, water dam – it would not exist without the Sun 2nd – Earth (nuclear fission) Hot geysers 3rd – Moon (gravitational force) When it moves ocean waters Anything else is just a secondary energy...
  24. B

    Where can I find sources for LCAO theory?

    any of you guyes know some decent sources for tight-binding (LCAO) theory? i wish to use the orbitals and the position of the atoms and the angle between the orbitals for calculating the resonance and overlap integrals, but it's hard to find specific sources... so if you happen to know any...
  25. I

    Power Sources in Series/Parallel ?

    Power Sources in Series/Parallel...? hey, I've got a question. say you had one power source that's about 4v and another that's about 3v. if you hooked them up in parallel the following power source would be (now im' pretty sure I am doing this right..if not..well I am not an electrical...
  26. A

    Need help on sources of magnetic fields

    Consider the current loop in the figure below. Figure: http://east.ilrn.com/graphing/bca/user/appletImage?dbid=1450953670 Determine the magnetic field (in terms of a, I and d) at the origin. So I will use mu as the permeability of free space. Since the two vertical wires have opposite...
  27. S

    Exploring Complex Numbers: Sources & Theories

    I've been attending at high school and I have some ideas about complex numbers. I shared my thoughts with my math teacher. He decided to search. I want to make sure if none have thought them so I need some information about complex numbers. Could you offer me some written sources and the...
  28. Astronuc

    Sources of Information on Engineering

    For those who would like some technical references, DOE Handbooks are available on line at: http://tis.eh.doe.gov/techstds/standard/standard.html Just click on the PDF link. Look for: DOE Fundamentals Handbook, Classical Physics, DOE-HDBK-1010-92 DOE Fundamentals Handbook...
  29. J

    What is the Calculation for Current in a Circuit with Two Sources of EMF?

    I have problem with a circuit. It has two sources of emf, and I'm not sure how to calculate the magnitued of the current in the circuit due to this. Here's what the circuit looks like (R's are resistors, *'s are just for spacing): |----------+|1|------| |*************** | R = 5...
  30. D

    Light Intensity at Point Sources: Impact on Energy Falloff?

    i am a little confused as to whether light intensity at a point source is critical to how the energy will fall off(i know inverse sq ). if there is equivalent intensity from 2 sources will there be the same energy at any given distance? sorry if that is a little convoluted... here is a more...
  31. P

    Can Rhodoferax Ferrireducens Bacteria Convert Sugar to Electricity?

    As many may know, the bacteria Rhodoferax ferrireducens has the ability to take various types of sugar and "convert" it into electricity. Many of you also know that gas prices have sky rocketed. Where am I getting here? I plan on doing a experiment using R. ferrireducens and ethanol from...
  32. L

    Sources of gravitational fields

    positive charges are sources of electric field and -ve charges are sink. what are sources and sink of gravitational fields?
  33. Y

    Correcting Data from Distant Sources for the Size of the Universe

    When the age of the universe is estimated via Hubble's Law (v = Hr), the photons that are received were emitted from sources that are now further away - so in the limit of the theory, H = c/R where R is the Hubble scale factor or Hubble Radius at the time the photon was emitted. Closeby...
  34. H

    Exploring Solar Cells and Renewable Energy Sources

    Does solar cell really only absorbs energy from sunlight? What about other sources of radiation such as thermal radiation? Wouldn't it be great if there are some devices that can recycles energy produced in major cities and convert it into electrical energy?
  35. D

    What Frequency Do You Hear from a Speeding Train's Whistle?

    A train is traveling toward you at 120km/h. The train blows its 400Hz whistle. take the speed of sound to be 340m/s. what's the frequency do you hear? f'=f/(1-vs/vo) 400/(1-(4.32x10^8 / 340)) i got 4.32x10^8 = 120000m * 3600sec what am i doing wrong? The possible answers are: which is...
  36. sheldon

    Can Alternative Energy Sources Meet Future U.S. Power Demand?

    As we know, the United States consumes more power than any other country in the world. The success of the U.S. can be directly related to its power consumption. Most of our electricity comes from burning fossil fuels (Coal) that puts Co2 in the atmosphere, this is causing major pollution. The...
  37. E

    Luminous vs. Nonluminous Light Sources

    what is the difference between a phosphorescent source and a fluorescent source? How does a flashlight can be luminous? How can it also be nonluminous? Which kind of light source would be safest to use in building or mines that may be filled with explosive gas?
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